Visceral fat meter provided with tonometer

ABSTRACT

A visceral fat scale equipped with a sphygmomanometer is described, with which a subject can keep track of blood pressure values and grasp the state of obesity to attain more accurate, comprehensive and diversified diagnoses and disease prevention. The visceral fat scale is designed such that after exerting pressure to an artery of a subject by inflation of a cuff, a pulse wave signal is detected in the course of gradual cuff deflation and blood pressure is obtained based on the detected pulse wave signal. The scale comprises an increment/decrement key and display mode selector key for inputting personal data of the subject; an arithmetic operation unit for calculating the amount of visceral fat of the subject based on data input by these keys; and a display unit for displaying a result of the calculation performed by the arithmetic operation unit.

TECHNICAL FIELD

The present invention relates to a visceral fat scale equipped with asphygmomanometer, which is capable of making simultaneous measurementsof blood pressure and percent body fat.

BACKGROUND ART

The latest studies have thrown considerable light upon the relationshipbetween hypertension and various diseases. People, who are generallydiagnosed as having hypertension, with a systolic blood pressure of 140mmHg or more and a diastolic blood pressure of 90 mmHg or more, commonlydevelop cerebral hemorrhage and cerebral infarction. In view of this,the importance of health care has been further emphasized in order toprevent diseases caused by high blood pressure. For effective preventionof hypertension, not only periodic medical check-ups such as bloodpressure taking but also awareness of the condition of blood pressure ona daily basis become necessary.

Recently, simplified sphygmomanometers which enable easy measurements ofblood pressure on a daily basis are commercially available so thatcontinuous, easy personal blood pressure control becomes possible. Forsuch simplified sphygmomanometers, the so-called oscillometric method(pressure pulse wave oscillation method) is prevailing which isdistinguished from the Korotcoff method that has been conventionallyused as the stethoscopy in the medical field and others. Theoscillometric method is carried out in such a manner that a cuff (armwrap) is worn around fingers, a wrist or an upper arm; air is sent tothe cuff to press an artery; pressure in the cuff is gradually releasedto detect pulse wave components with a pressure sensor; and bloodpressure (systolic and diastolic blood pressures) is measured based onthe detected pulse wave components.

A known electronic sphygmomanometer utilizing the oscillometric methodis designed as follows: For setting of a target inflation value for thecuff, a cuff pressure signal is detected, for example, during inflationof the cuff. Then, a systolic blood pressure (e.g., a cuff pressurecorresponding to one-half the maximum amplitude of the pulse wave) issimply estimated from the maximum amplitude value of the pulse waveincluded in the signal, and a value obtained by adding a specified valueto the estimated systolic blood pressure is automatically set as atarget inflation value. In this case, for the purpose of reducing thetime required for a blood pressure measurement as well as the pain givento the person under measurement, the rising speed of pressure at thetime of cuff inflation is set to a higher value than the speed of cuffdeflation during which a measurement of systolic and diastolic pressuresis made.

In the medical field, there have recently been advances in the studiesof the association between hypertension and obesity and it has beenfound that obesity is not simply a state of overweight and thedistribution of body fat bears relevance to blood pressure. It has beenfurther reported that the distribution of abdominal body fat (visceralfat type obesity) deeply concerns hypertension.

In addition to BMI (Body Mass Index=body weight/(body height)²) that iswidely used as an index indicative of the degree of obesity, variousindices (e.g., percent body fat, the cross-sectional area of abdominalvisceral fat, etc.) to an assessment of visceral fat type obesity havebeen devised and respectively proved to be useful in the clinical sites.Of these indices, percent body fat is obtained based on personalspecific data on the subject such as height, weight, age and sex andbased on the measurement of body impedance. The cross sectional area ofabdominal visceral fat is obtained from a CT scan of the abdomen of thesubject around his umbilicus and from estimation based on data on thewaist size of the subject obtained by measuring the abdomen of thesubject around his umbilicus as well as the personal specific datadescribed above.

The above-described conventional sphygmomanometer has, however, revealedsuch a drawback that since it measures and deals with blood pressurealone, it cannot provide more accurate diagnosis of hypertension takingaccount of the relationship with the aforesaid visceral fat typeobesity.

In addition, the conventional sphygmomanometer of this type presentsanother problem when setting a target inflation value for the cuff.Specifically, since the conventional sphygmomanometer is susceptible tothe influence of noise caused by the fluctuation of a cuff pressuresignal occurring just after cuff inflation, the detection of a pulsewave at the time of cuff inflation cannot be always carried outcorrectly, so that an estimated value of systolic blood pressure and, inconsequence, a target inflation value based on the estimated valuebecome wrong. Especially, if the target inflation value is set to anabnormally low value, there will occur an error in the later measurementof blood pressure values (i.e., systolic blood pressure and diastolicblood pressure) at the time of cuff deflation due to a lack ofinflation.

The present invention has been directed to overcoming the foregoingshortcomings and a primary object of the invention is therefore toprovide a visceral fat scale equipped with a sphygmomanometer with whicha subject can keep track of his blood pressure values and grasp thestate of obesity to realize more accurate, comprehensive and diversifieddiagnoses and disease prevention. Another object of the invention is toprovide a visceral fat scale equipped with a sphygmomanometer whereineven if it fails in making an accurate measurement of the maximumamplitude value of a pulse wave at the time of cuff inflation, an errorwill not occur in the measurement of blood pressure values at the timeof cuff deflation.

DISCLOSURE OF THE INVENTION

The above objects can be accomplished by a visceral fat scale equippedwith a sphygmomanometer according to a first aspect of the invention,wherein after exerting pressure to an artery of a subject by inflationof a cuff, a pulse wave signal is detected in the course of gradual cuffdeflation and blood pressure is obtained based on the detected pulsewave signal, the visceral fat scale comprising:

an input device for inputting personal data of the subject;

an arithmetic operation unit for calculating the amount of visceral fatof the subject based on the data input by the input device; and

a display unit for displaying a result of the calculation performed bythe arithmetic operation unit.

According to the invention, since the amount of visceral fat of asubject is calculated by the arithmetic operation unit based on personaldata input by the input device and the result of the calculation isdisplayed on the display unit, the subject can keep track of his bloodpressure values and grasp the amount of visceral fat, in other words,the state of obesity, so that control of blood pressure in connectionwith visceral fat type obesity becomes possible. This enables moreaccurate, comprehensive, diversified diagnoses and disease preventionwith a simplified device, compared to the conventional health managementbased on blood pressure alone.

Preferably, in the invention, the personal data input by the inputdevice includes the height, weight and waist size of the subject, andthe arithmetic operation unit calculates the BMI of the subject inaddition to the amount of visceral fat of the subject based on the datainput by the input device. This makes it possible to calculate not onlythe amount of visceral fat but also BMI (Body Mass Index) that isinternationally used as an index to an assessment of obesity/emaciation,so that more reliable data on the state of obesity can be attained.

In this case, the display unit preferably displays the ranks of thevisceral fat amount and BMI of the subject, these indices respectivelyhaving a plurality of ranks. By representing the degree of obesityaccording to the ranks of the indices, the subject can more easily makea self assessment of the degree of obesity.

Preferably, the arithmetic operation unit makes an assessment of obesityby comparing the visceral fat amount and BMI of the subject with theirrespective reference values for assessment which have been inputbeforehand, and wherein the display unit displays a result of theassessment of obesity.

The display unit preferably displays blood pressure values and theamount of visceral fat at the same time. This allows the subject tograsp his blood pressure values and the state of obesity on a firstviewing of the display unit.

In addition, it is preferable that the arithmetic operation unitcalculate the amount of change from a previous measurement result andthe ratio of the present measurement result to the previous measurementresult for the blood pressure values and visceral fat amount of thesubject, and that the display unit display a result of the calculation.With this arrangement, the subject can more accurately grasp his stateof health through the relationship between the degree of change in hisblood pressure and the degree of change in the amount of visceral fat ofhis own, so that he can utilize the acquisition for proper health careand disease prevention.

The amount of visceral fat may be the cross-sectional area of abdominalvisceral fat of the subject which is used as an index to an assessmentof obesity in the clinical site. Herein, the target cuff inflation valuemay be determined by a systolic blood pressure estimated based on apulse wave generated during cuff inflation and by the cross-sectionalarea of abdominal visceral fat. Alternatively, the target cuff inflationvalue may be determined by a systolic blood pressure estimated based ona pulse wave generated during cuff inflation and by a result of anassessment of obesity. With this arrangement, even if the maximumamplitude value of a pulse wave generated during cuff inflation cannotbe correctly measured, there will not occur such an unfavorablesituation that blood pressure values (systolic blood pressure anddiastolic blood pressure) to be measured at the time of cuff deflationbecome incorrect owing to a lack of inflation.

According to a second aspect of the invention, there is provided avisceral fat scale equipped with a sphygmomanometer, wherein afterexerting pressure to an artery of a subject by inflation of a cuff, apulse wave signal is detected in the course of gradual cuff deflationand blood pressure is obtained based on the detected pulse wave signal,the visceral fat scale comprising:

an input device for inputting personal data including the height, weightand waist size of the subject;

electrodes for current application and electrodes for measurement whichare brought into contact with part of the body of the subject;

a body impedance measuring unit for measuring the body impedance of thesubject based on a signal from the measurement electrodes;

an arithmetic operation unit for calculating at least any of the BMI,percent body fat and visceral fat amount of the subject based on datainput by the body impedance measuring unit and data input by the inputdevice; and

a display unit for displaying a result of the calculation performed bythe arithmetic operation unit.

In addition to the first aspect, the invention has the feature that thebody impedance of the subject is measured and, based on thismeasurement, the percent body fat of the subject is calculated anddisplayed. Therefore, the subject can more accurately grasp not only hisblood pressure values but also the state of obesity and, accordingly,the effect of the first aspect is enhanced.

Preferably, in the invention, the display unit displays the rank of anyof the BMI, percent body fat and visceral fat amount of the subject,each of these indices having a plurality of ranks. With thisarrangement, the subject can more easily make an assessment of thedegree of obesity of his own.

Preferably, the arithmetic operation unit makes an assessment of obesityby comparing any of the BMI, percent body fat and visceral fat amount ofthe subject with their respective values for assessment which have beeninput beforehand, and the display unit displays a result of theassessment of obesity.

The display unit preferably displays blood pressure values and theamount of visceral fat at the same time. This allows the subject tograsp his blood pressure values and the state of obesity on a firstviewing of the display unit.

In addition, it is preferable that the arithmetic operation unitcalculate the amount of change from a previous measurement result andthe ratio of the present measurement result to the previous measurementresult for the blood pressure values and visceral fat amount of thesubject, and that the display unit display a result of the calculation.

The amount of visceral fat may be the cross-sectional area of abdominalvisceral fat of the subject which is used as an index to an assessmentof obesity in the clinical site. Herein, the target cuff inflation valuemay be determined by a systolic blood pressure estimated based on apulse wave generated during cuff inflation and by the cross-sectionalarea of abdominal visceral fat. Alternatively, the target cuff inflationvalue may be determined by a systolic blood pressure estimated based ona pulse wave generated during cuff inflation and by a result of theassessment of obesity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a general perspective view of a visceral fat scale equippedwith a sphygmomanometer according to a first embodiment of theinvention.

FIG. 2 is a block diagram of the visceral fat scale equipped with asphygmomanometer according to the first embodiment.

FIG. 3 is a flow chart (the first stage) of the operation of thevisceral fat scale equipped with a sphygmomanometer according to thefirst embodiment.

FIG. 4 is a flow chart (the second stage) of the operation of thevisceral fat scale equipped with a sphygmomanometer according to thefirst embodiment.

FIGS. 5(a) and 5(b) are explanatory graphs showing a blood pressuremeasuring method according to the first embodiment.

FIG. 6 is a general perspective view of a visceral fat scale equippedwith a sphygmomanometer according to a second embodiment.

FIG. 7 is a block diagram of the visceral fat scale equipped with asphygmomanometer according to the second embodiment.

FIG. 8 is a flow chart (the first stage) of the operation of thevisceral fat scale equipped with a sphygmomanometer according to thesecond embodiment.

FIG. 9 is a flow chart (the second stage) of the operation of thevisceral fat scale equipped with a sphygmomanometer according to thesecond embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring now to the accompanying drawings, there will be describedpreferred embodiments of a visceral fat scale equipped with asphygmomanometer according to the invention.

FIGS. 1 and 2 show a general perspective view and block diagram,respectively, of a visceral fat scale equipped with a sphygmomanometeraccording to a first embodiment of the invention.

The visceral fat scale equipped with a sphygmomanometer 1 of thisembodiment is designed to measure blood pressure, using the so-calledoscillometric blood pressure measuring method (the pressure pulse waveoscillation method) and has as main components, a machine body 2 and acuff (arm wrap) 4 which is connected to the machine body 2 through anair tube 3 and wearable around an arm of a subject. Disposed within themachine body 2 is an air supply unit 5 which is connected to the airtube 3 and comprised of a pump for supplying the cuff 4 with air and apressure release valve for releasing the air pressure of the cuff 4, andothers. An air pressure sensor 6 is also disposed within the machinebody 2, for detecting pulse wave components through detection of the airpressure of the cuff 4. The air supply unit 5 and the air pressuresensor 6 are connected to a central processing unit (arithmeticoperation unit) 8 through an I/O circuit 7.

The machine body 2 has, at its top face thereof, a display unit 9 andinput keys/switches 14 which are comprised of a power switch 10, a bloodpressure measurement starting switch 11, an increment/decrement key 12,and a display mode selector key 13. Further, the central processing unit8 is provided with a memory 15 for storing data such as personal datawhich has been input by the input keys/switches 14 and sent to thememory 15 through the I/O circuit 7. It should be noted that theincrement/decrement key 12 and the display mode selector key 13correspond to the input device of the present invention.

Reference is made to the flow charts of FIGS. 3 and 4 to describe theoperation of the visceral fat scale equipped with a sphygmomanometer 1having the above structure. Note that code S stands for a step.

S1: The power switch 10 is turned ON to put the machine body 2 intooperation.

S2: The display mode selector key 13 and the increment/decrement key 12are operated thereby selectively inputting the personal data of thesubject such as height, weight and waist size. The data thus input isstored in the memory 15.

S3: Based on the personal data stored in the memory 15, the centralprocessing unit 8 calculates the BMI and abdominal visceral fatcross-sectional area (AV) of the subject and the results of thecalculations are stored in the memory 15. The arithmetic expressionsused for the above calculations have been stored in the memory 15beforehand and are called into the central processing unit 8 whenexecuting the arithmetic operations. As the simplest expression forobtaining abdominal visceral fat cross-sectional area (AV), thefollowing regression equation (1) is used:AV=a ₁ ×W _(L) +d ₁  (1)where W_(L) is waist size. The coefficient a₁ and constant d₁ of thisexpression are derived from a statistic technique such as regressionanalysis, based on the correlation between the waist size and abdominalcross-section C/T data of a selected group of subjects.

S4: The BMI and abdominal visceral fat cross-sectional area (AV) whichhave been calculated and stored in the memory 15 at step S3 are comparedto their reference values set for the obesity assessment. The rank ofobesity for the subject is determined and stored in the memory 15. Thereference values and arithmetic expression used for the comparison havebeen stored in the memory 15 and are called into the central processingunit 8 when executing the arithmetic operations. As the reference valuesfor the obesity assessment, BMI=25 (for male and female) and abdominalvisceral fat cross-sectional area (AV)=100 cm² (for male and female) areused. It should be noted that BMI is internationally used as an index toan assessment of obesity/emaciation and abdominal visceral fatcross-sectional area (AV) represents the amount of distributed visceralfat and is used for diagnoses of obesity in the clinical site. Obesityis ranked according to these indices BMI and AV. More concretely, BMI isclassified as follows: the range of 25 to 30 is rank I, the range of 30to 35 is rank II and the range of more than 35 is rank III. Abdominalvisceral fat cross-sectional area (AV) is classified as follows: therange of 100 to 125 cm² is rank I, the range of 125 to 150 cm² is rankII and the range of more than 150 cm² is rank III.

S5: Subsequently, the cuff 4 is worn around an arm of the subject forblood pressure measurement.

S6: The blood pressure measurement starting switch 11 is depressed,thereby starting blood pressure measurement.

S7: The air supply unit 5 supplies the cuff 4 with air so that the cuff4 is inflated.

S8: The pressure of the cuff 4 is detected by the air pressure sensor 6while the cuff 4 being inflated and a pulse wave to be superimposed on apressure signal is detected in the course of the inflation of the cuff4. The maximum value Amax′ of the amplitude of the pulse wave isobtained to be stored in the memory 15 (See FIG. 5).

S9: To estimate a systolic blood pressure P₁′ from the maximum amplitudevalue Amax′ of the pulse wave, an amplitude value A₁′, for example, isobtained which is one α-th (1/α) the maximum amplitude value Amax′ ofthe pulse wave, in other words, which is derived from the followingequation:A 1′=1/α×Amax′  (2)

S10: Then, the cuff pressure (estimated systolic blood pressure) P₁′corresponding to the amplitude value A₁′ obtained at step S9 is obtainedand stored in the memory 15.

S11: To determine a target cuff inflation value based on the estimatedsystolic blood pressure P₁′, the estimated systolic blood pressure P₁′is compared to a specified value (which is, herein, 100 mmHg).

S12: If the estimated systolic blood pressure P₁′ is less than 100 mmHg,a check is made to determine whether or not each index (BMI and AV)exceeds its reference value, in other words, whether BMI>25 and AV>100cm² hold. This check is made in order to determine a target cuffinflation value P_(k) as security for errors in the measurement andestimation, based on the result of the assessment of obesity with thestored obesity indices (BMI and AV).

S13: If obesity is diagnosed based on the judgement with the indices(BMI and AV), in other words, if BMI>25 and AV>100 cm² hold, the targetcuff inflation value P_(k) is determined from the equation (3):Pk=140 mmHg+20×β  (3)

where β represents a value looked up in Table 1 with an obesity rank I,II or III.

TABLE 1 OBESITY RANK I II III BMI β = 1 β = 1.5 β = 2 AV β = 1 β = 2   β= 3

Since the determining factor for the target cuff inflation value P_(k)thus takes account of the result of the obesity assessment, there willnot occur such an undesirable situation that blood pressure values(i.e., systolic blood pressure and diastolic blood pressure) areincorrectly measured during later cuff deflation, even if themeasurement of the maximum amplitude value Amax′ of the pulse wavegenerated during cuff inflation is not correctly made owing toinsufficient inflation.

S14: If at least either index BMI or AV does not indicate obesity in thejudgement of Step S12, the target cuff inflation value P_(k) isdetermined by the following equation (4):Pk=140 mmHg (4)

In this way, the estimated systolic blood pressure P₁′ is compared tothe specified value (100 mmHg) based on the measurement of the maximumamplitude value Amax′ of the pulse wave generated during cuff inflation,and if it is determined that the estimated value P₁′ is less than thespecified value and obesity is not diagnosed in the obesity assessment,the target cuff inflation value P_(k) is set to the lowest limit value(e.g., 140 mmHg). With this arrangement, if an error occurs in themeasurement of the maximum amplitude value Amax′ and in the calculationof the estimated systolic blood pressure P₁′, the target cuff inflationvalue P_(k) will be set to its lowest limit value so that occurrence ofan undesirable situation can be avoided in which the measurement ofblood pressure values (i.e., systolic blood pressure and diastolic bloodpressure) is incorrectly made during later cuff deflation.

S15: If it is judged at step S11 that the estimated systolic bloodpressure P₁′ is 100 mmHg or more, a check is then made similarly to thestep S12 to determine whether each of the indices (BMI and AV) exceedsits reference value for the obesity assessment, in other words, whetherBMI>25 and AV>100 cm² hold.

S16: If at least either of the indices BMI and AV does not indicateobesity, the target cuff inflation value P_(k) is determined by thefollowing equation (5):P_(k)=P₁′+40 mmHg (5)

S17: On the other hand, if both indices BMI and AV indicate obesity, inother words, if BMI>25 and AV>100 cm² hold, the target cuff inflationvalue P_(k) is determined by the following equation (6):

 P _(k) =P ₁′+20×β+30  (6)

S18: After the target cuff inflation value P_(k) has been determined inthe above-described manner, cuff inflation is carried out until the cuffpressure reaches the target cuff inflation value P_(k) and then stopped.

S19: After it is judged that the cuff inflation has stopped, the valveof the air supply unit 5 is switched to the evacuation side so thatextremely slow deflation of the cuff 4 starts.

S20: A pulse wave to be superimposed on a pressure signal in the cuffdeflation phase is detected and the maximum amplitude value Amax of thepulse wave is obtained and stored. Then, in order to estimate a systolicblood pressure P₁ from the maximum amplitude value Amax of the pulsewave, an amplitude value A₁ which is one α-th (1/α) the maximumamplitude value Amax′ of the pulse wave, for example, is obtained, inother words, the amplitude value A₁ is obtained from the followingequation (7):A 1=1/α×Amax  (7)

To estimate a diastolic blood pressure P₂ from the maximum amplitudeAmax of the pulse wave, an amplitude value A₂ which is one γ-th (1/γ)the maximum amplitude value Amax′ of the pulse wave, for example, isobtained, in other words, the amplitude value A₂ is obtained from thefollowing equation (8):A 1=1/γ×Amax  (8)

The value of 1/α may be 0.5, whereas the value of 1/γ may be 0.7. Inplace of 1/α and 1/γ, an estimate equation or the like which providesmore improved estimation accuracy may be used.

S21: After completion of the measurement of systolic blood pressure anddiastolic blood pressure, the evacuation of the cuff 4 is done by rapiddeflation within a short time and then, the deflation of the cuff 4 isstopped.

S22: The blood pressure measurement is completed.

S23: After completion of the measurement, the display unit 9 performsselective displaying of the input data such as the personal data(height, weight, sex, age, waist size), the blood pressure measurements(systolic blood pressure and diastolic blood pressure), the indices (BMIand abdominal visceral cross-sectional area) used for the obesityassessment, the result of the assessment, and the degree of obesity (therank of each index).

The visceral fat scale equipped with a sphygmomanometer 1 of thisembodiment may be designed such that data on blood pressuremeasurements, BMI and abdominal visceral cross-sectional area is storedeach time a measurement is made and each data piece is displayed withthe amount of change from the result of the previous measurement. Inaddition, the scale 1 may display the ratio of the present measurementresult to the previous measurement result (or the ratio of the changebetween the present and previous measurement results to the previousmeasurement result) in terms of blood pressure values and abdominalvisceral cross-sectional area. This makes it possible to get an idea ofthe relationship between the amount of change and the aforesaid ratiowith respect to the amount of distributed abdominal visceral fat andblood pressure values, and therefore, health condition can be moreaccurately grasped based on these values to achieve more adequate healthcontrol. Additionally, changes in each data item may be recordedaccording to a systematic schedule of blood pressure measurements,thereby observing the long-term transition of data and making use of itas a guideline for diagnosis.

FIGS. 6 and 7 show a general perspective view and block diagram,respectively, of a visceral fat scale equipped with a sphygmomanometeraccording to a second embodiment of the invention.

The visceral fat scale equipped with a sphygmomanometer 1A of the secondembodiment has the function of measuring body impedance to obtain thepercent body fat of the subject in addition to the same function as thatof the visceral fat scale equipped with a sphygmomanometer 1 of thefirst embodiment. The parts identical to those of the first embodimentare indicated with the same reference numerals as in the firstembodiment and a detailed explanation of them will be omitted herein.

The visceral fat scale equipped with a sphygmomanometer 1A of the secondembodiment has electrodes 16 which are positioned at the front and backfaces of the upper right and upper left ends of a machine body 2A andthe fingers (e.g., a thumb and an index finger) of both hands of thesubject touch the electrodes 16. By pinching each electrode 16 with thefingers of each hand, the body impedance between the fingers of the handis measured by a body impedance measuring circuit 17, and themeasurement data is input to the central processing unit 8 through theI/O circuit 7 and stored in the memory 15. Based on the measurementdata, percent body fat is calculated. On the upper face of the machinebody 2A, a percent body fat measurement starting switch 18 is providedin addition to the same input keys/switches as in the first embodiment.Herein, each electrode 16 is comprised of, for instance, an electrodefor measurement disposed on the front face of the machine body 2A and anelectrode for current application disposed on the back face of the same.Reference numeral 19 of FIG. 6 designates a stand for setting themachine body 2A up.

Next, the operation of the visceral fat scale equipped with asphygmomanometer 1A of the second embodiment will be described withreference to the flow charts of FIGS. 8 and 9. It should be noted thatcode T stands for a step.

T1: The power switch 10 is turned ON to put the machine body 2 intooperation.

T2: By depressing the display mode selector key 13 and theincrement/decrement key 12, the personal data of the subject such asheight, weight, sex and waist size is selectively input. The data thusinput is stored in the memory 15.

T3: After the percent body fat measurement starting switch 18 has beenturned ON thereby making the scale ready for percent body fatmeasurement, the fingers of both hands are brought into contact with theelectrodes 16 to measure the body impedance between the fingers of bothhands and the measurement data is stored in the memory 15.

T4: The percent body fat of the subject is calculated based on themeasurement data on the body impedance and the personal data stored inthe memory 15, and the result of the calculation is stored in the memory15. In the central processing unit 8, the BMI of the subject iscalculated based on the personal data while performing calculation ofthe abdominal visceral fat cross-sectional area (AV) of the subjectbased on the personal data and the data on the body impedance or percentbody fat. The results of the calculations are stored in the memory 15.The arithmetic expressions used for the above calculations have beenstored in the memory 15 beforehand and are called into the centralprocessing unit 8 when executing the arithmetic operations. As theexpression for obtaining abdominal visceral fat cross-sectional area(AV), the following regression equation (9) is used, which is obtainedby adding the auxiliary term of body impedance (Z) to the expression (1)used in the first embodiment:AV=a ₂ ×W _(L) +b ₂ ×Z+d ₂  (9)

where W_(L) is waist size. The coefficients a₂, b₂ and constant d₂ ofthis expression are derived from a statistic technique based on thecorrelation between the waist size and abdominal cross-section C/T dataof a selected group of subjects.

Instead of the regression expression (9), the following regressionexpression (10) may be used which is obtained by adding percent body fat(FAT) as an auxiliary term.AV=a ₃ ×W _(L) +c ₁×FAT+d ₃  (10)

The coefficients a₃, c₁ and constant d₃ of this expression are alsoderived from a statistic technique based on the correlation between thewaist size and abdominal cross-section C/T data of a selected group ofsubjects.

Further, the following expression (11) may be used which provides ahigher coefficient of correlation (r=0.9 or more) for the C/T data:AV=e ₁ ×W _(L) ² ×H _(L)×FAT+f ₁ ×W _(L) ² ×H _(L)×Age+d ₄  (11)

where H_(L) is height and Age is age. The coefficients e₁, f₁ and theconstant d₄ are derived from a statistic technique based on thecorrelation between the abdominal cross-section C/T data and values I,II of a selected group of subjects. Herein, the value I is obtained bymultiplying the square of waist size by height and percent body fat,whereas the value II is obtained by multiplying the square of waist sizeby height and age.

Alternatively, the following equation (12) may be used:AV=f ₂ ×W _(L) ² ×H _(L)×Age+g ₁×FAT+d ₅  (12)

The coefficients f₂, g₁ and constant d₅ of this equation are derivedfrom a statistic technique based on the correlation between theabdominal cross-section C/T data, percent body fat, and a value of aselected group of subjects, the value being obtained by multiplying thesquare of waist size by height and age.

T5: The BMI, percent body fat and abdominal visceral fat cross-sectionalarea (AV), which have been calculated at step T4 and stored in thememory 15, are compared to their respective reference values used forthe obesity assessment and the rank of obesity is determined to bestored in the memory 15. The reference values and equation used for theabove comparative operations have been stored in the memory 15 andcalled into the central processing unit 8 when executing the arithmeticoperations.

As the reference values for the assessment of obesity, BMI=25 (for maleand female), percent body fat (male: 20%, female: 30%), and abdominalvisceral fat cross-sectional area (AV)=100 cm² (for male and female) areused. It should be noted that BMI is an index internationally used forassessment of obesity/emaciation, whereas abdominal visceral fatcross-sectional area (AV) represents the amount of distributed visceralfat and is used as an index to diagnosis of obesity in the clinicalsite. Obesity is ranked according to the indices BMI, percent body fatand AV. More specifically, BMI is classified as follows: the range of 25to 30 is rank I, the range of 30 to 35 is rank II and the range of 35 ormore is rank III. Percent body fat is classified as follows: for male,the range of 20 to 25% is rank I, the range of 25 to 30% is rank II andthe range of more than 30% is rank III, and for female, the range of 30to 35% is rank I, the range of 35 to 40% is rank II, and the range ofmore than 40% is rank III. Abdominal visceral fat cross-sectional area(AV) is classified as follows: the range of 100 to 125 cm² is rank I,the range of 125 to 150 cm² is rank II and the range of 150 cm² or moreis rank III.

The steps T6 to T24 to be performed onward are basically the same as thesteps S5 to S23 of the first embodiment except the following points: Thesteps T13 and T16 differ from the steps S12 and S15 of the firstembodiment in that a check is made at the steps T13 and T16 whether ornot percent body fat (FAT) exceeds 20% (in the case of male) or 30% (inthe case of female). The step T24 differs from the step S23 of the firstembodiment in that the display contents of the display unit 9 at thestep T24 includes percent body fat as an index to the assessment ofobesity. In view of this, a detailed description of the steps T6 to T24will be omitted herein.

In the foregoing embodiments, the abdominal visceral fat cross-sectionalarea of the subject is obtained from the input personal data of thesubject (height, weight, age, sex, waist size etc.), using an arithmeticexpression stored beforehand. Herein, waist size may be estimated fromthe input data on the height, weight and age of the subject. An exampleof the equation used for this estimation is the following equation (13):W _(L) =m ₁ ×W/H _(L) ² ×n ₁×Age+1₁  (13)where W is weight, H_(L) is height, and Age is age.

Based on the waist size which has been obtained from the abovearithmetic operation and the personal data (height, weight, age, sexetc.) of the subject, the abdominal visceral fat cross-sectional area ofthe subject may be calculated with the arithmetic expression used in theforegoing embodiments. This saves the trouble of measurement andinputting of waist size, so that visceral fat can be more readilyobtained.

1. A visceral fat scale equipped with a sphygmomanometer comprising acuff, wherein after exerting the cuff exerts pressure to an artery of asubject by inflation of the cuff, the sphygmomanometer obtains the bloodpressure of the subject based on a detected pulse wave signal, and thevisceral fat scale comprising: an input device for inputting personaldata of the subject; an arithmetic operation unit for calculating theamount of visceral fat of the subject based on the data input by theinput device, the amount of visceral fat being the cross-sectional areaof abdominal visceral fat of the subject; and a display unit fordisplaying a result of the calculation performed by the arithmeticoperation unit.
 2. The visceral fat scale equipped with asphygmomanometer according to claim 1, wherein the personal data inputby the input device includes the height, weight and waist size of thesubject and wherein the arithmetic operation unit calculates the bodymass index (BMI) of the subject in addition to the amount of visceralfat of the subject based on the data input by the input device.
 3. Thevisceral fat scale equipped with a sphygmomanometer according to claim2, wherein the display unit displays the respective ranks of thevisceral fat amount and BMI of the subject, each of said indices havinga plurality of ranks.
 4. The visceral fat scale equipped with asphygmomanometer according to claim 2 or 3, wherein the arithmeticoperation unit makes an assessment of obesity by comparing the amount ofvisceral fat and BMI of the subject with their respective referencevalues for assessment which have been input beforehand, and wherein thedisplay unit displays a result of the assessment of obesity.
 5. Thevisceral fat scale equipped with a sphygmomanometer according to claim1, wherein the display unit displays blood pressure values and theamount of visceral fat at the same time.
 6. The visceral fat scaleequipped with a sphygmomanometer according to claim 1, wherein thearithmetic operation unit calculates the amount of change from aprevious measurement result and the ratio of the present measurementresult to the previous measurement result for blood pressure values andvisceral fat amount of the subject, and wherein the display unitdisplays a result of the amount of change and ratio calculation.
 7. Thevisceral fat scale equipped with a sphygmomanometer according to claim1, wherein a target inflation value for the cuff is determined by asystolic blood pressure estimated based on a pulse wave generated duringcuff inflation and by a result of the assessment of obesity.
 8. Thevisceral fat scale equipped with a sphygmomanometer according to claim1, wherein a target inflation value for the cuff is determined by asystolic blood pressure estimated based on a pulse wave generated duringcuff inflation and by the cross-sectional area of abdominal visceralfat.
 9. A visceral fat scale equipped with a sphygmomanometer comprisinga cuff, wherein, after the cuff exerts pressure to an artery of asubject by inflation of the cuff, the sphygmomanometer obtains the bloodpressure of the subject based on a detected pulse wave signal, and thevisceral fat scale comprising: an input device for inputting personaldata including the height, weight and waist size of the subject;electrodes for current application and electrodes for measurement whichare brought into contact with part of the body of the subject; a bodyimpedance measuring unit for measuring the body impedance of the subjectbased on a signal from the measurement electrodes; an arithmeticoperation unit for calculating at least any of the body mass index(BMI), percent body fat and visceral fat amount of the subject based ondata input by the body impedance measuring unit and data input by theinput device, said visceral fat amount being the cross-sectional area ofabdominal visceral fat of the subject; and a display unit for displayinga result of the calculation performed by the arithmetic operation unit.10. The visceral fat scale equipped with a sphygmomanometer according toclaim 9, wherein a target inflation value for the cuff is determined bya systolic blood pressure estimated based on a pulse wave generatedduring cuff inflation and by the cross-sectional area of abdominalvisceral fat.
 11. The visceral fat scale equipped with asphygmomanometer according to claim 9, wherein the display unit displaysthe rank of any of the BMI, percent body fat and visceral fat amount ofthe subject, each of said indices having a plurality of ranks.
 12. Thevisceral fat scale equipped with a sphygmomanometer according to claim 9or 11, wherein the arithmetic operation unit makes an assessment ofobesity by comparing any of the BMI, percent body fat and visceral fatamount of the subject with their respective reference values forassessment which have been input beforehand, and wherein the displayunit displays a result of the assessment of obesity.
 13. The visceralfat scale equipped with a sphygmomanometer according to claim 9, whereinthe display unit displays blood pressure values and the amount ofvisceral fat at the same time.
 14. The visceral fat scale equipped witha sphygmomanometer according to claim 9, wherein the arithmeticoperation unit calculates the amount of change from a previousmeasurement result and the ratio of the present measurement result tothe previous measurement result for blood pressure values and visceralfat amount of the subject, and wherein the display unit displays aresult of amount of change ratio calculation.
 15. The visceral fat scaleequipped with a sphygmomanometer according to claim 9, wherein a targetinflation value for the cuff is determined by a systolic blood pressureestimated based on a pulse wave generated during cuff inflation and by aresult of the assessment of obesity.